/*
 * This file is part of the eccOS Library.
 * Copyright (C) 2007.
 *
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 */
package org.openeccos.dao;

import java.io.Serializable;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.List;
import java.util.Vector;

import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.criterion.Order;
import org.hibernate.criterion.ProjectionList;
import org.hibernate.criterion.Projections;
import org.hibernate.criterion.Restrictions;

import com.sas.framework.expojo.RepositoryComponent;
import com.sas.framework.expojo.hibernate.HibernatePersistenceProvider;


/**
 * @author cgspinner@web.de
 */
public abstract class AbstractPageableDataSource extends RepositoryComponent implements IPageableDataSource {

	public static final String NAME = "AbstractPageableDataSource";
	public String getName() { return NAME; }

	protected abstract void setParameter(Criteria criteria, Object[] params);

	protected ProjectionList getProjection() {
		ProjectionList projectionList = Projections.projectionList();
		projectionList.add(Projections.id(), "id");
		projectionList.add(Projections.property("cachedTitle"),  "title");
		return projectionList;
	}

	protected HeaderValue getHeaderValue(Object[] data) {
		HeaderValue headerValues = new HeaderValue();
		headerValues.identifier = (Serializable)data[0];
		headerValues.title = (String)data[1];
		return headerValues;
	}

	public PagableResult getResult(int currentTopRow, int rowsPerPage, Object[] params) {
		PagableResult result = new PagableResult();
		result.setHeaders(new Vector<HeaderValue>());

		//first load the new item(s)
		Criteria criteria = getSession().createCriteria(getModelClass());
		criteria.add(Restrictions.isNotNull("newEntryDate"));
		criteria.addOrder(Order.desc("newEntryDate"));
		List list = criteria.list();
		for (int i = 0; i < list.size(); i++) {
			HeaderValue headerValue = getHeaderValue((Object[])list.get(i));
			if (i == 0) {
				headerValue.isEditing = true;
			}
			result.getHeaders().add(headerValue);
		}
		int newItems = list.size();
		
		if (list.size() < rowsPerPage) {
			criteria = getSession().createCriteria(getModelClass());
			setParameter(criteria, params);
	
			criteria.setFirstResult(currentTopRow);
			criteria.setMaxResults(rowsPerPage - list.size());
			criteria.setProjection(getProjection());
			criteria.add(Restrictions.isNull("newEntryDate"));
			list = criteria.list();		
		}
		
		for (Object data : list) {
			result.getHeaders().add(getHeaderValue((Object[])data));
		}

		criteria.setProjection(Projections.rowCount());
		criteria.setFirstResult(0);

		result.setRowCount((Integer)criteria.uniqueResult() + newItems);
		return result;
	}

	private Session getSession() {
		HibernatePersistenceProvider hpp = (HibernatePersistenceProvider)modelExposer.getPersistenceProvider();
		return hpp.getSession();
	}
}